Two RCTs were included for review (n=158 patients). Both trials scored 1 point on the Jadad scale; neither reported sufficient detail on randomisation, blinding, allocation concealment or withdrawals.
Ginseng combined with conventional therapy significantly improved cognitive function compared to conventional therapy alone, as assessed using the Mini-Mental State Examination (MMSE, WMD 1.85, 95% CI 0.88 to 2.82; n=158 patients) and the Alzheimer's Disease Assessment Scale (ADAS) cognitive subscale (WMD 3.09, 95% CI 1.08 to 5.09; n=158 patients). Addition of ginseng to conventional therapy did not significantly improve non-cognitive function as assessed using the ADAS. There was no evidence of statistical heterogeneity for any of these outcomes (I2 = 0%).
Subgroup analyses revealed that ginseng continued to significantly improve cognitive function at doses of 4.5g daily as measured using the MMSE (WMD 1.80, 95% CI 0.71 to 2.90; n=128 patients) and the ADAS (WMD 3.03, 95% CI 0.93 to 5.14; n=128 patients).
Adverse events reported in the included studies were fever, nausea, diarrhoea, headache, dizziness, sensitivity to heat and anorexia.